High quality power ramping in a communications transmitter

A method of controlling ramping of a communications signal including amplitude modulation between two states including a state of minimal output power of the communications signal during which no information is conveyed and a state in of greater output power in which information is conveyed, the method comprising producing an envelope signal having a ramp-up portion, a ramp-down portion, and a flat portion between the ramp-up portion and the ramp-down portion wherein:

• the ramp-up portion is produced based on a first half of a communications pulse signal, a squared magnitude of the Fourier transform of the communications pulse signal being approximately proportional to the power spectrum of the communications signal;
• and
• the ramp-down portion is produced based on a second half of the communications pulse signal.

Circuitry for controlling ramping of a communications signal including amplitude modulation between two states including a state of minimal output power of the communications signal during which no information is conveyed and a state of greater output power in which information is conveyed, the method comprising:

• means for adding a predetermined sequence of symbols to a sequence of information symbols to be communicated to form an augmented sequence of symbols;
• and
• a first modulator for performing modulation of the augmented sequence of symbols to produce an envelope signal that exhibits a desired ramp profile.

A ramp generator for controlling ramping of a communications signal including amplitude modulation between two states including a state of minimal output power of the communications signal during which no information is conveyed and a state in of greater output power in which information is conveyed, by producing an envelope signal having a ramp-up portion, a ramp-down portion, and a flat portion between the ramp-up portion and the ramp-down portion, comprising:

• storage for storing first values corresponding to the ramp-up portion, the first values being based on a first half of a communications pulse signal, and for storing second values corresponding to the ramp-down portion, the second values being based on a second half of the communications pulse signal, a squared magnitude of the Fourier transform of the communications pulse signal being approximately proportional to the power spectrum of the communications signal;
• and
• control circuitry responsive to timing signals for causing the first values to be read out during a ramp-up interval and for causing the second values to be read out during a ramp-down interval.